The present invention relates generally to manufactured seeds and, more particularly, to a system for the delivery of plant embryos to various growing platforms.
Modern agriculture, including silviculture, often requires the planting of large numbers of substantially identical plants genetically tailored to grow optimally in a particular locale or to possess certain other desirable traits. Production of new plants by sexual reproduction can be slow and is often subject to genetic recombinational events resulting in variable traits in its progeny. As a result, asexual propagation has been shown for some species to yield large numbers of genetically identical embryos, each having the capacity to develop into a normal plant. Such embryos must usually be further cultured under laboratory conditions until they reach an autotrophic xe2x80x9cseedlingxe2x80x9d state characterized by an ability to produce their own food via photosynthesis, resist desiccation, produce roots able to penetrate soil and fend off soil microorganisms.
Some researchers have experimented with the production of artificial seeds, known as manufactured seeds, in which individual plant somatic or zygotic embryos are encapsulated in a seed coat, such as those disclosed in U.S. Pat. No. 5,701,699, issued to Carlson et al., the disclosure of which is hereby expressly incorporated by reference.
Typical manufactured seeds include a seed coat, a synthetic gametophyte and a plant embryo. The seed coat is usually a capsule having a closed end and an open end. The synthetic gametophyte is placed within the seed coat, such that it substantially fills the seed coat. A cotyledon restraint may be centrally located within the synthetic gametophyte. The cotyledon restraint includes a centrally located cavity extending partially through its the length and is sized to receive the plant embryo therein. The well known plant embryo includes a radicle end and a cotyledon end. The plant embryo is deposited within the cavity of the cotyledon restraint cotyledon end first. The plant embryo is typically sealed within the seed coat by at least one end seal.
In the past, delivery of the plant embryo within the seed coat has utilized a liquid-based transport system to move the plant embryo through the manufactured seed production line. In such a liquid-based transport system, plant embryos are placed in a container of liquid to orient them in a like direction. The plant embryos are caused to float to the top of the container, such that each embryo floats upwardly within the container cotyledon end first. From the top of the container, additional liquid is used to propel the plant embryos out of the container while maintaining their cotyledon end first orientation. Liquid is then used to transport the plant embryos through the remaining manufactured seed production line steps. Although such liquid-based plant embryo delivery systems are effective at transporting plant embryos, they are not without their problems.
First, both system response and plant embryo movements through the system are slow because electromechanical actuators are required for controlling the liquid flow. Second, handling of the plant embryo is not precise. Often it is difficult to manipulate a plant embryo suspended in liquid, as it is difficult to manipulate any objects suspended in liquid. Third, it is difficult to reliably detect plant embryos because of their small size, the requirement for a large diameter transport tube, and cavitation in the liquid. Additionally, it is difficult to analyze each plant embryo for quality when it is suspended in liquid. Further, removing all of the liquid after the plant embryo is placed in the cavity of the cotyledon restraint is difficult. Removing all of the liquid from the embryo is desirable because liquid may cause early germination or rot. Slow throughput of the liquid system requires multiple liquid systems to meet the overall production quantity goals. Finally, the large numbers of components in a liquid delivery system present reliability problems, as well as difficulties in maintaining the system.
Thus, there exists a need for a plant embryo delivery system that is capable of reliably producing a large number of manufactured seeds at a relatively low cost, and minimizing the risk of damaging or contaminating the plant embryo.
In accordance with one embodiment of the present invention, a method of delivering cultivated plant embryos is provided. The method includes the step of orientating a plurality of embryos in a predetermined orientation. The method also includes analyzing each of the plurality of embryos according to a predetermined quality criteria to identify qualified plant embryos. Further, the steps of determining the positional measurements of the qualified embryos, and positioning a first seed coat relative to the qualified embryos are also included in the method of the present invention. The method further includes the step of inserting one of the qualified embryos in the seed coat according to the positional measurements of the qualified embryos to minimize damage to and contamination of the qualified embryos.
The method of delivering a plant embryo of the present invention has several advantages over currently available plant embryo delivery systems. The delivery system of the present invention uses mini-robotic pick and place systems with motion control to increase the speed and accuracy of the embryo delivery system. Embryo manipulation is transformed from a non-precise environment to a precise environment at the front end of the embryo processing on the manufacturing line. In a robotics system, precise information about an object and the ability to move that object with precision allows the opportunity to move the object faster. The overall system is simpler because it utilizes computerized electronics and machine control equipment. Using less components and, therefore, less equipment results in a more reliable system. Further, liquid is removed from around the embryo as one of the first process steps, thereby eliminating the potential for liquid contamination of the cotyledon restraint. Finally, electronically viewing the embryo is simpler without liquid in the path of viewing.
Thus, a method of delivering plant embryos in a manufactured seed formed in accordance with the present invention has a high degree of reliability, and is able to mass produce manufactured seeds or deliver embryos in a given orientation in a plate, greenhouse container or other seed designs. Further such a method for delivering plant embryos also minimizes the risk of damaging or contaminating the plant embryo during the process of manufacturing the seed.